1. Field of the Invention
The present invention relates to a direct cranking electric rotary machine to be mounted on a vehicle.
2. Description of the Related Art
A direct cranking electric rotary machine for a vehicle has been widely known. Such a direct cranking electric rotary machine is used for starting an internal combustion engine mounted on a vehicle, assisting the torque of the engine, and generating electric power to be supplied to various types of electrical loads mounted on the vehicle. Japanese patent laid open publication No. JP H11-078555 has disclosed such a direct cranking electric rotary machine. A rotor in the direct cranking electric rotary machine also acts as a flywheel for the internal combustion engine mounted on the vehicle
However, such a direct cranking electric rotary machine makes repair and examination work much more difficult because of being always placed between the internal combustion engine and a power transmission system such as a clutch device and a transmission device. Further, because the rotation speed of the internal combustion engine of a vehicle is low at starting and a large torque is required, it is necessary to incorporate a direct cranking electric rotary machine acting as a flywheel of a large diameter into the vehicle in order to output high power energy. However, the increase of the diameter of the flywheel increases its weight, namely the weight of the direct cranking electric rotary machine. Increasing the weight of the direct cranking electric rotary machine is not practical in use.